RF430FRL152H: safely writing to memory using ISO15693 Block Write

Hello Jason,

Okay so I'm a bit confused here because it sounds like you are crossing two different applications here.

For configuring the device via virtual registers, you cannot be in NFC/NDEF mode. If that is the situation, then you have to pick one or the other. Either a non-NFC setup with virtual registers, or using NDEF messaging and not having access to the virtual registers.

If I am mistaken about this, please help clarify which example project you are working from so I can look into it further.

Also the reader side, I am guessing you are using SLOC297 and the ISO15693_sendWriteSingleBlock API?

Hi Ralph,

Thanks for the quick response!

For configuring the device via virtual registers, you cannot be in NFC/NDEF mode. If that is the situation, then you have to pick one or the other. Either a non-NFC setup with virtual registers, or using NDEF messaging and not having access to the virtual registers.

I want to use NFC/NDEF mode, not the virtual registers. When I wrote "configuration parameters", I'm talking about some functionality specific to my application (I actually want to configure the parameters of a PWM module) which is not supported by the main application.

If I am mistaken about this, please help clarify which example project you are working from so I can look into it further.

I am working off the NFC_Only sample application. One thing that might be relevant is that I changed the size of the FRAM_NDEF and FRAM_CODE sections in the linker file:

    // code area, can be increased /  decreased
    // FRAM_NDEF + FRAM_CODE lengths must equall 0x768 (with FRAM_NDEF starting at 0xF868)
    // Two sections together in the range of 0xF868-0xFFCF
    FRAM_NDEF               : origin = 0xF868, length = 0x0018 // ends at 0xF8CF - NDEF memory section
    FRAM_CODE               : origin = 0xF880, length = 0x0750 // ends at 0xFFCF - Firmware memory section

Also the reader side, I am guessing you are using SLOC297 and the ISO15693_sendWriteSingleBlock API?

Yup, that's right. But really I am not tied to using ISO15693, if it's easier to accomplish with custom commands I could do that instead. The only reason I used ISO15693 was because it's what was supported in SLOC297.

Thanks,

Jason

Hi Ralph,

Obvious now that you point it out! I adjusted the block number I am writing to and that seems to have fixed it.

On the SLOC297 side I have modified the NFC_appIso15693 function a bit as shown below. (Note, I defined START_BLOCK as 0x0A. But I adjusted to use 0x02 and this seems to fix the problem.)

...
if (ui8TagFound == STATUS_SUCCESS)
	{
		if (ISO15693_getTagCount() > 1)
		{
#ifdef ENABLE_HOST
			UART_putNewLine();
			UART_sendCString("Multiple ISO15693 Tags Found");
			UART_putNewLine();
			UART_sendCString("# of Tags Detected: ");
			UART_putByteDecimalValue(ISO15693_getTagCount());
			UART_putNewLine();
			UART_sendCString("Place only 1 tag in RF Field to read data");
			UART_putNewLine();
#endif
		}
		else
		{
		    unsigned int block_num = 0;
		    for (block_num = START_BLOCK; block_num < START_BLOCK+2; block_num++)
            {
                if (ISO15693_sendReadSingleBlock(0x02 | ui8AddressedFlag, block_num) == STATUS_FAIL) // Keep reading blocks unless a No Response is received
                {
                    LED_15693_OFF;
                    // No Response - stop reading
                    break;
                }
            }

            if (NFCwrite()) {
                // NDEF Header
                uint8_t b1[4] = {0xE1, 0x40, 0x79, 0x00};
                uint8_t r = ISO15693_sendWriteSingleBlock(0x42 | ui8AddressedFlag, 0x00, 4, b1);
                uint8_t b2[4] = {0x03, 0x0B, 0xD5, 0x00};
                r = ISO15693_sendWriteSingleBlock(0x42 | ui8AddressedFlag, 0x01, 4, b2);

                uint8_t* p = getNFCPayload(); // returns a pointer to the new data to be written to the tag
                unsigned int num_bytes = 12;
                unsigned int block_num = START_BLOCK;
                while (num_bytes > 0) {
                    unsigned int bytes_to_write = 4;

                    uint8_t b[4];
                    memcpy(b, p, 4);

                    r = ISO15693_sendWriteSingleBlock(0x42 | ui8AddressedFlag, block_num, bytes_to_write, b);

                    block_num += 1;
                    p += bytes_to_write;
                    num_bytes -= bytes_to_write;
                }
            }
		}
	}

As one last question then, am I correct in assuming I can use the NDEF memory as arbitrary storage in the NFC_Only example?

Thanks,

Jason